add: ability to create seller account

crates/core/src/model/auth.rs

@@ -334,6 +334,8 @@ pub struct UserSettings {
 pub struct StripeSellerData {
     #[serde(default)]
     pub account_id: Option<String>,
+    #[serde(default)]
+    pub completed_onboarding: bool,
 }
 
 fn mime_avif() -> String {